Lupus is an autoimmune disease in which the immune system mistakenly attacks healthy tissues all throughout the body. Because of this, lupus can present symptoms in areas such as the joints, kidneys, blood, heart, and lungs. The most common form of lupus is systemic lupus erythematosus.
Cutaneous lupus erythematosus (CLE) is a form of lupus that specifically attacks the skin. CLE can manifest in those already with lupus, or it can occur on its own. In fact, CLE is very common in people who already have lupus and occurs in about 85% of those with lupus.
Research continues to suggest a link between vitamin D and autoimmune disease. While past research has looked at an overall link between vitamin D and lupus, there hasn’t been much research looking at vitamin D and CLE.
Therefore researchers from Hospital de la Vega Lorenzo Guirao, Murcia, Spain, were interested in vitamin D’s role in disease severity of those with CLE, and if supplementation can help at all.
We covered this study in our vitamin D and systemic lupus erythematosus health summary, but in this blog, I’m going to give a detailed look at it.
Researchers conducted this study in two stages. The first stage was observational and compared vitamin D levels of 60 patients with CLE to the vitamin D levels of 117 matched healthy participants.
Were there differences in the vitamin D levels? Here’s what they found:
- Those with CLE had average vitamin D levels of 20 ng/ml compared to the healthy participants who had average levels of 26 ng/ml (p=0.001).
- After adjusting for things like sun exposure and sunscreen use, CLE was associated with an increased risk of being vitamin D deficient.
The second stage of the study was an intervention trial. They gathered the CLE patients from the first stage who had vitamin D levels lower than 30 ng/ml and split them into a vitamin D intervention group and a control group. The vitamin D group received 1,400 IU/day of vitamin D and 1,250 mg/day of calcium for 40 days. After the 40 days, the group received 400 IU and 1,250mg calcium twice a day for one year. The control group received nothing. After one year, the patients were assessed by a dermatologist who was blinded to which group each patient belonged to.
Did the vitamin D supplementation help CLE at all? Here’s what they found:
- Vitamin D levels in the vitamin D group increased from an average 17 ng/ml at baseline to 30 ng/ml (p=0.001).
- CLASI A score decreased significantly from 2.7 at baseline to 0.9 (p=0.003) in the vitamin D group and did not significantly change in the control group. CLASI D score remained relatively unchanged in both groups. CLASI, the Cutaneous Lupus Disease Area and Severity Index, is a tool used to measure disease severity in CLE. The tool measures disease activity (CLASI A) and damage (CLASI D) on 13 different body areas to give a numerical score. A lower score reflects less severity and a higher score reflects more disease severity.
- In the first stage of the study, which took place over 185 days, the researchers recorded 118 days and 82 days of active lesions in the vitamin D and control groups, respectively. Over the course of the year, the vitamin D group experienced a significant decrease to 56 days of active lesions (p=0.009) and the control group experienced a non-significant decrease to 65 days (p=0.37). The researchers didn’t mention why the treatment group had significantly higher baseline days of active lesions.
- During the patient assessment, none of the patients in the vitamin D group thought their disease severity had gotten worse over the year compared with 16% of the patients in the control group who thought their disease severity had gotten worse.
The researchers concluded,
“Our data show that the 25(OH)D levels in the CLE patients are significantly lower than in the controls, and that having CLE increases the odds of inadequate serum 25(OH)D levels, even after adjusting for sun exposure and sunscreen use. However, the most important finding of this study is that vitamin D supplementation may have improved disease activity scores in our patients with vitamin D insufficiency.”
The researchers note that their small sample size and lack of a placebo and randomization are limitations to their study. Additionally, they recognize that the dose of vitamin D used in their study was low and higher doses might show a stronger effect.
We also can’t say for sure if the effect on CLE is from vitamin D alone, calcium alone or from the two combined.
This study, as with other experimental research in lupus, presents a promising potential for the use of vitamin D in those with CLE. In the future, we need even larger trials looking at the link between vitamin D and lupus.